When 2015 began, it seemed unfathomable by the end of the year that Brian Williams would no longer anchor "NBC Nightly News" or that Donald Trump would be leading in the polls for the 2016 Republican presidential nomination.
But both circumstances factored into the mixed ratings performance for TV news on cable and the major broadcast networks. Here's how they fared in the ratings over the last year:
After a few years of declining or flat ratings the channels have seen a boost from interest in the 2016 presidential campaign, which intensified with the rise of real estate mogul and reality show star Trump. His candid and at times...